Injection valve for internal combustion engines

Abstract

An injection valve is indicated for internal combustion engines, having a sealing seat formed by a valve seat and a closing head of a valve needle, and having a plurality of spray holes situated downstream from the sealing seat. The spray holes, which are stepped in cross-section, each have at least one upstream hole inlet section having a very small hole cross-section and a hole inlet opening, and a downstream hole outlet section having a very large hole cross-section and a hole outlet opening. In order to prevent unwanted deposition of burnt fuel on the edges of the hole outlet openings, all the hole outlet sections are connected to one another by a groove having a groove opening that points downstream.

Description

FIELD OF THE INVENTION[0001]The present invention is based on an injection valve for internal combustion engines.BACKGROUND INFORMATION[0002]A known fuel injection valve for internal combustion engines, described in German Published Patent Application No. 10 2005 036 951 and realized as a so-called multi-hole injection valve, has a valve seat element that terminates a hollow cylindrical valve seat bearer and that limits a valve chamber that stands in connection with a fuel supply line. In the valve seating element, there are fashioned a valve seat in the form of an annular surface concentrically surrounding the axis of the valve seat element, and a large number of spray holes. Together with a closing element of a valve member disposed so as to be axially displaceable in the valve seat bearer, the valve seat forms a sealing seat that terminates the spray holes. The valve member is acted on by a valve closing spring that presses the closing head onto the valve seat. An electromagnetic...

AI Technical Summary

Benefits of technology

The present invention provides an injection valve that allows air to flow from outside into the hole outlet sections via a groove, which connects all the hole outlet sections of the spray holes, to improve ventilation and modify pressure conditions. The valve closing phase prevents the formation of a vacuum that would draw the fuel film, built up during the injection phase, in the direction of the hole outlet openings, reducing the likelihood of deposits and keeping soot emission relatively constant over the engine's lifespan. Additionally, the width of the groove is smaller than the diameter of the hole outlet openings, which creates turbulence in the air flow, ensuring good ventilation.

Problems solved by technology

However, it has turned out that the flow exiting from the spray holes at the end of the injection produces a vacuum region in its wake, due to its inertia, and this vacuum draws the fuel film that builds up on the wall of the hole outlet openings during injection in the direction of the outlet edge of the hole outlet openings.

Due to the poor preparation quality, the latter do not participate adequately in the combustion, causing an increase in soot emissions.

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